Should you really feed a cold and starve a fever?

You’ve probably heard the old saying “Feed a cold, starve a fever.” But is there any truth to it?

Well, that’s still up for debate. But a recent study suggests it’s probably not as accurate as your mom always led you to believe. In fact, there may be a new adage to guide you next time you’re feeling under the weather: Feed a virus, starve bacteria.

Yale researchers found that mice were able to recover more quickly from bacterial infections when they didn’t eat anything. However, the opposite was true for mice with viral infections—eating sped up recovery times.

In the first part of their experiment, researchers infected mice with bacteria that often cause food poisoning — Listeria monocytogenes.

Now, as you would expect if you’ve ever had food poisoning, these mice did not feel like eating at all. The researchers let some of these mice go without food, but others they forced to eat. And guess what happened?

The mice that didn’t eat eventually recovered, but the mice that were force-fed died. So next time a bacteria-based stomach bug steals your appetite, listen to your body. On the other hand, if you have a cold or flu (both of which are viruses) eating could be good for you…

In stage two of the experiment, researchers infected mice with a flu virus. They force-fed glucose to some of these mice, and others they didn’t feed at all. In this case, the mice receiving nourishment fared much better than the ones that didn’t — the mice that ate survived, the mice that didn’t died.

Of course, these studies were done on mice. Who knows how this theory would work on humans? Researchers plan to test that out eventually.

But in the meantime, you should still put some careful thought into what to eat when you’re sick. Certain foods might help the healing process, while others might hinder it. And clearly, in some situations (like when you have a bacterial infection from food poisoning) no food is your best bet.

Researchers say when you’re dealing with a non-life-threatening infection like a run-of-the-mill cold or flu, you should go with your gut: Eat what your body is craving. It might be your body’s way of telling you what it needs to fight the infection.

Of course, there are some hard and fast guidelines for eating when you’re under the weather. When you have a cold, for example, you should consume a lot of hot liquids to fight phlegm, like broth-based soups and hot tea. You’ll also want to eat foods that are high in vitamin C like citrus fruits to boost your immune system. And, if you’re congested, you can try something spicy to clear out those nasal passages.

The flu, on the other hand, takes a softer touch — especially if you’re dealing with nausea. You’ll want to stick to blander foods like a bowl of oatmeal with banana to restore your electrolytes. Of course chicken soup is a no-brainer… According to Dr. Isaac Eliaz, it’s one of the top 10 foods for immune health. And studies have shown than even store-bought chicken soup can reduce symptoms of cold and flu.

You can also try stomach-soothing beverages like ginger and peppermint tea. Drinking fruit and vegetable juices is another easy way to get some nutrients in you.

And this probably goes without saying, but regardless of what you eat, always make sure you’re drinking plenty of water. Dehydration is a surefire way to stay sick longer no matter what type of infection you have.

Sources:

1. Wang, et al. “Opposing Effects of Fasting Metabolism on Tissue Tolerance in Bacterial and Viral Inflammation.” Cell, 2016; 166 (6): 1512-1525.

2. “Feed a virus but starve bacteria? When you’re sick, it may really matter.” Medical Xpress. http://medicalxpress.com. Retrieved September 28, 2016.

3. “Exactly What To Eat When You Have A Cold Or Flu.” Prevention. http://www.prevention.com. Retrieved September 28, 2016.